World View : Deadly Malaria Comes Back With a Vengeance : The tropical disease rages through sub-Saharan Africa and parts of Asia and Latin America. In one Pacific capital, everyone is infected.

HONIARA, Solomon Islands — It is a dubious distinction perhaps, but eager medical researchers from distant lands flock to this sleepy, southwest Pacific capital just to take blood samples from the citizens.

The reason: Honiara has the world's highest recorded incidence of malaria, the single-celled, mosquito-borne parasite that has frustrated science for more than a century. Last year, in fact, Honiara achieved the seemingly impossible: Thanks to repeat cases, it registered 1,120 bouts of malaria for every 1,000 residents.

More importantly, malaria has grown worse worldwide in the past decade, according to the World Health Organization. Indeed, United Nations statistics show it's the only major disease other than AIDS that is steadily spreading today. More than 1 million people--mostly children under 5--die each year from a disease that is both curable and preventable.

Most malaria deaths are in sub-Saharan Africa, where drought and starvation lower resistance, control programs are lacking and there are few clinics or drugs to treat the victims. But the infection rate also has risen in scores of other tropical countries after a World Health Organization decision in 1969 to abandon a 20-year worldwide effort to eliminate the disease.

"It was realized eradication was not achievable," said John Storey, malaria scientist at the U.N. agency's Western Pacific regional headquarters in Manila. "So we switched emphasis to control."

There was little choice. Despite some successes, both the parasite and the mosquitoes that carry it proved far hardier than expected. No anti-malaria vaccine corresponding to the vaccine against smallpox has been found--despite years of effort. And wholesale spraying of DDT, a powerful insecticide that wipes out malaria-carrying mosquitoes, was stopped due to environmental damage and high costs.

Once the spraying stopped, the disease came back with a vengeance. Today, malaria rages in parts of Asia and Latin America where "it had been considerably reduced or eliminated during the 1960s and 1970s," reports World Health, the official WHO magazine. In Africa, "the situation is worsening all the time."

Nearly half the world's population, in 103 countries from Afghanistan to Zambia, is at risk from malaria. The World Health Organization estimates that 270 million people now carry the parasite, and 110 million suffer recurring flu-like attacks of aching bones, fiery fever, icy chills and worse. Cerebral or falciparum malaria, the most dangerous of four malaria parasites, can kill within hours.

Partly to focus attention on the growing problem, WHO will hold a global conference on malaria this October in Amsterdam. Dozens of health ministers are expected to adopt a worldwide control strategy.

Experts say malaria is worsening for several reasons.

New roads, logging and irrigation have drawn people into tropical jungles and other once-isolated areas where mosquitoes swarm. Refugees, migrants and tourists have spread the disease across borders. Urban drift, poverty and poor sanitation have returned it to cities where it once was eliminated.

And most worrisome, the foe is far stronger. In many areas, the Anopheles mosquito, which transmits malaria, is increasingly resistant to insecticides. Even worse, the malaria parasites are increasingly resistant to chloroquine, the drug most widely used for prophylaxis and treatment. New drug treatments are less effective and much more expensive.

In Cambodia, for example, a particularly virulent and drug-resistant strain of cerebral malaria threatens the U.N. peacekeeping forces, as well as several hundred thousand refugees awaiting repatriation. Although conditions vary from place to place, this parasite is now resistant to chloroquine, fanzidar, quinine and mefloquine, a powerful drug once used as a last resort.

"Though mines are killing perhaps two to four people a day, malaria is killing very many more," said Dr. Jean-Paul Menu, the U.N. health agency's representative in Cambodia.

U.N. troops are using doxycycline, a broad-spectrum antibiotic that so far appears effective. They also sleep under insecticide-doused nets, wear long sleeves and take other precautions.

Meanwhile, new drugs are being sought. The best hope is arteether, derived from an herb used to fight fevers for more than 2,000 years in China. WHO says it "may well be the most important natural extract" against malaria since quinine was isolated from cinchona bark in 1834. Field tests of arteether are under way or planned in Vietnam, Papua New Guinea, Kenya and Nigeria.